The present invention relates to the discovery of two new chemicals that can be used for the treatment, prevention, or amelioration of hyperproliferative diseases and/or disorders such as cancer. It finds particular application in conjunction with cancer such as colon cancer, and will be described with particular reference thereto.
Hyperproliferation is used to describe aberrant/dysregulated cellular growth, a hallmark of diseases like cancer. Currently, cancer therapy may involve surgery, chemotherapy, hormonal therapy and/or radiation treatment to eradicate neoplastic cells in a patient (see, for example, Stockdale, 1998, “Principles of Cancer Patient Management”, in Scientific American: Medicine, vol. 3, Rubenstein and Federman, eds., Chapter 12, Section IV). Recently, cancer therapy could also involve biological therapy or immunotherapy. All of these approaches pose significant drawbacks for the patient. Surgery, for example, may be contraindicated due to the health of the patient or may be unacceptable to the patient. Additionally, surgery may not completely remove the neoplastic tissue. Radiation therapy is only effective when the neoplastic tissue exhibits a higher sensitivity to radiation than normal tissue, and radiation therapy can also often elicit serious side effects. Hormonal therapy is rarely given as a single agent and although can be effective, is often used to prevent or delay recurrence of cancer after other treatments have removed the majority of the cancer cells. Biological therapies/immunotherapies are limited in number and may produce side effects such as rashes or swellings, flu-like symptoms, including fever, chills and fatigue, digestive tract problems or allergic reactions.
With respect to chemotherapy, many potential drugs have been discovered in the last 30 years for treating hyperproliferative disease and/or disorder such as cancer. Actually, a large number of different cancers are treated successfully and produce strong remissions that often prevent the cancers from regaining strength. The mechanisms by which these results are obtained are to kill the cells by interfering with the reproductive machinery of cell replication. For example, standard cancer chemotherapeutic drugs kill cancer cells upon induction of programmed cell death (“apoptosis”) by targeting basic cellular processes and molecules. These basic cellular processes and molecules include RNA/DNA (alkylating and carbamylating agents, platin analogs and topoisomerase inhibitors), metabolism (drugs of this class are named anti-metabolites and examples are folic acid, purin and pyrimidine antagonist) as well as the mitotic spindle apparatus with αβ-tubulin heterodimers as the essential component (drugs are categorized into stabilizing and destabilizing tubulin inhibitors; examples are Taxol/Paclitaxel®, Docetaxel/Taxotere® and vinca alkaloids). A significant majority of cancer chemotherapeutics act by inhibiting DNA synthesis, either directly, or indirectly by inhibiting the biosynthesis of the deoxyribonucleotide triphosphate precursors, to prevent DNA replication and concomitant cell division (see, for example, Gilman et al., Goodman and Gilman's: The Pharmacological Basis of Therapeutics, Eighth Ed. (Pergamom Press, New York, 1990)). These agents, which include alkylating agents, such as nitrosourea, anti-metabolites, such as methotrexate and hydroxyurea, and other agents, such as etoposides, campathecins, bleomycin, doxorubicin, daunorubicin, etc., although not necessarily cell cycle specific, kill cells during S phase because of their effect on DNA replication. Other agents, specifically colchicine and the vinca alkaloids, such as vinblastine and vincristine, interfere with microtubule assembly resulting in mitotic arrest.
Despite the availability of a variety of chemotherapeutic agents, chemotherapy has many drawbacks (see, for example, Stockdale, 1998, “Principles Of Cancer Patient Management” in Scientific American Medicine, vol. 3, Rubenstein and Federman, eds., ch. 12, sect. 10). Almost all chemotherapeutic agents are toxic, and chemotherapy causes significant, and often dangerous, side effects, including severe nausea, bone marrow depression, immunosuppression, etc. Additionally, even with administration of combinations of chemotherapeutic agents, many tumor cells are resistant or develop resistance to the chemotherapeutic agents. In fact, those cells resistant to the particular chemotherapeutic agents used in the treatment protocol often prove to be resistant to other drugs, even those agents that act by mechanisms different from the mechanisms of action of the drugs used in the specific treatment; this phenomenon is termed pleiotropic drug or multidrug resistance. Thus, because of drug resistance, many cancers prove refractory to standard chemotherapeutic treatment protocols.
Because some of these drugs are carefully designed to interfere with the replication of fast growing cells, they also often interfere with the replication of those non-carcinogenic cells that also constantly replicate, such as hair, gut lining and so on. As a result, these drugs have to be used at low doses in order to minimize the terrifying effects of the treatments. The challenge is therefore how to create potent and specific cancer cells killing agents, or inhibiting agents with minimal side effects, and, notably without killing other reproducing cells.
Advantageously, the invention provides a method for treating, preventing or ameliorating a hyperproliferative disease and/or disorder such as cancer with minimal or none of the side effects often associated with chemotherapy. By not killing normal reproducing cells, drugs which do not exhibit high potency can be used at large doses which might still be sufficient to realize the medical objective.